Traveling grate



F. B. FORREST TRAVELING GRATE File Dec. 23 1918 3 Sheets-Sheet 1 i /wagaj awew Dec. 1924- 1,518,783

F. B. FORREST TRAVEIJI NG GRATE Filed Dec. 25, 1918 3 Sheets-Sheet 2 a 14 13/5, j/ d,

1 5752275 iii 07 71366 Z. w yg Dec. 9, 1924. 1,518,783

F. B. FORREST TRAVELING GRATE F iled Dec. 25, 1918 :5 Sheets-Sheet 5 l'fijlmii IIHIIIIIII l 1 A! MWeitiY)? Zunk 712 070 652? Patented Dec. 9, 1924.

1,518,783 PATENT OFFICE.

rum: 3. FORREST, or Mffiafd'ltn, MASSACHUSETTS.

TRAVELING GRATE.

Application filed December 23,1918. Serial N70. 267,961.

To all whom it may concern:

Be it known that I, FRANK B. FORREST,

a citizen of the United States, residing at Med-ford, in the county of MiddleseX and State of Massachusetts, have invented certain new and useful Improvements in Traveling Grates, of which the following is a specification.

My invention relates to improvements in traveling grates for use in furnaces as a part of a mechanical stoker, in which the fuel as it burns is carried on the grate through the furnace.

One of the objects of the invention is to provide a traveling grate having segmental fuel plates that do not touch at the fire level and are held in position by means below the fire level, thereby preventing the grate bars composed of these fuel plates from growing or increasing in length, as is common with all grates in general use, through the effect of the repeated heating by the fire in causing the expansion of the metal in the case of solid grate bars and the accumulation of scale and clinkers in grate bars built up of fuel plates or in sections. Therefore, the grate remains at substantially its original size and form and cannot buckle, warp or bind at the sides of the furnace, which would 1n "either case retard or prevent 1ts movement.

Another object is to provide atraveling grate having a substantially continuous air or draft'space at the fire level clear across and the entire length of the grate and draft spaces entirely around the fuel plates, thereby permitting a draft of air to surround the fuel plates, thus keeping them from fusing,

and the air 'to be readily distributed uniformly to the entire fuel bed.

Another object is to provide interfitting fuel plates that will so draw apart, as' they pass over the sprockets, that they. will automatically clear themselves of o'linkers and crusts.

the upper edges of the fuel plates and thus bringing most of the upper surface "and the points .or ends below the fire level.

Another object is to provide means for imparting an undulating movement to the grate bars and consequently to the fin-like members of the fuel plates and bar end caps, whereby the fuel bed is cracked up automatically and the air thus allowed to freely :pass' through the mass of fuel of the fuel bed, while the undulating movement of the fin-like members constantly clears of ashes the draft spaces surrounding them.

Another object is to provide a traveling grate inclined from the front to the rear,

grate bars made in one piece, or a series of chain links forming a belt for the fuel bed, which do not permit of easy repair and do not maintain the mass of fuel in a proper condition for perfect combustion, either through insuficient air draft or too violent disturbance of the fuel bed, while my traveling grate, employing grate bars fixedly held in the chain links and having assembled therein a: plurality of separate fuel plates and bar end caps with interfitting fin-likc members having ample intervening draft spaces around them, keeps the fuel of even thickness and delivers the air evenly throughout the fuel bed, and, moreover, perunits the ready renewal of the fuel plates and bar end caps at slight cost.

"ll'lOjlTOf one of the grate bars and co-operating parts of the travelin grate, sections -of which only are shown in order to show the entire width of the grate'bar. Fig. 3 is a plan of a group of adjoining fuel plates and bar end caps. Figs. 4 and 5 are plans of single and double interfitting bar end caps respectively[ Fig. '6 is a side elevation of one of the center bar caps, which are the same in side elevation of the bar end caps shown in Figs. 4, 5 and 18. Figs 7 and 8 are end elevations of 'a single center bar cap and a double center bar cap respectively. Fig 9 is a "plan, Fig. 10 is a side elevation and Fig. 11 a section on the line 11-11 of Fig. 10, of one of the fuel plates. Fig. 1.2 is a side elevation of two co-operating assembling bars, partly in section, showing the elevation of a section of one of the chain bearer bars and a chain roller and bearing lug. Fig. 18 is a side clevati n of a link plate with a bar end capinserted therein together with co-operating parts.

Latitude is allowed herein as to details, since they may be varied or changed at will without departing from the spirit or scope of my invention.

Corresponding and like parts are referred to in the following description and indicated in all the figures of the drawings by the same reference characters.

In the drawings 1 designates a traveling grate installed in a furnace 2, which is provided with a hopper 3, from which the coal is fed by gravity to the traveling grate 1, which is inclined from the front to the rear so as to produce more rapid ignition of the fuel. The traveling grate 1 consists of a series of grate bars, 4:, each of which is mounted in link plates 5 and G forming links of endless driving chains 7, which travel on rollers 8 suitably mounted on paired and spaced bearer bars 9 below the driving chains 7, and located at each end of the grate bars 41 on each side of the fur nace 2 adjacent to the side plates 10 enclosing the grate, while the inner end of the traveling grate 1 extends over the ash pit 2 of the furnace 2. The side plates 10 are mounted on wheels 11, so that the whole structure may be readily removed from the furnace, when repairs or renewal of grate bars are necessary. are operated by sprockets 12 and over idler sprockets 18 at the other end of the chains 7, which are provided on each side of the grate 1 with suitable chain ten sion device 1-1- for adjusting the chains Y.

Each grate bar 4- consists of a series of segmental fuel plates 1o assembled on an assembling bar 16, preferably a T-bar or a rectangular bar, which extends across the furnace. The fuel plates 15 are-in plan rhomboidal or similarly shaped and are provided with lateral, tapered fin-like members 17, each fuel plate 15 having an upper fuel supporting surface 18 in the form of longitudinal center ridge 18 and a bev- The driving chains 7- eled portion 18 on each side thereof, the center ridge 1S being arched or curved downwardly toward each end in order to keep the edges and the points of the tinlilce memb rs 17 out of the fire and thereby prevent their fusing. The sides of the upper fuel supporting surface 18 of each of the fuel plates 15 are tapered longitudinally prefer to employ for this purpose fuel plates so formed that each fuel plate 15 has the upper fuel supporting surface 18 provided with sides in planes parallel to the planes of the corresponding sides of the adjoining fuel plates, as shown in Fig. 3, so that when he assembling bars 16 with their fuel plates 15 mounted thereon are arranged in parallel position in the traveling grate 1, the fuel plates 15 on the successive assembling bars 16 will be staggered and interfit with each other as thereby to form the maximum fuel supporting surface possible to form of independent, segmental fuel plates. Further, the fin-like members 17 of the fuel plates 15 on each assemblingbar 16 are adapted to extend over to substantially the center of the adjoining assembing bar 16 on each side, while all the successive, co-operatin fuel plates 15 in. each row are aligned end to end with each other and have. a

clearance therebetween, so that when the adjoining assembling bars 16 and their fuel plates 15 pass over the sprockets 13, they will draw apart and tilt, thus slicing and clearing away all clinkers and ashes tlmroughly, not only from around but from between all the adjoining and aligned fuel plates 15' j p In the body portion 19 of each fuel plate 15 is a bar locking opening 20, through which the bar 16 passes and in which it fits. Adjoining the bar locking opening 20 on each side thereof is a sparing lug or flange 21 adapted to extend imvardly as well. as along each side of the bar 16 and to hold apart aoining fuel plates 15 in spaced rela-- tion to each other and to hold the fuel plates 15 in a fixed position on the assembling bar 16, thereby provit 'ng an air draft entirely around each fuel plate 15 clear up to its-upper fuel supporting surface 18 and the'tire level, by which means a substantially continuous air space is provided entirely around the fuel plates 1: clear to the fire level as well as clear acrossand the entire length the grate.

Each of the links of the driving chains 1 Lil ill

is composedof apair of spaced link plates, so that a pair of inner; link plates 5 is joined to a pair of outer link plate s' 6, as shown in Fig. 14:, and'ateach end the inner and outer link plates overlapeach other and are separated by a roller spacer-'22 held; in positionby a pin 23 and" adapted to revolve freely thereon, whichpin 23ffpasses through the ends of the adjoining pairs of, inner and outer link plates 5 and 6 and is riveted on each end, thereby holdingthe inner and outer link plates 5 and 6, as well as the roller spacers 22 securely in position and forming a complete link, lnserted in each link a bar end cap 24 or being arranged in alternation in the chain 7 as hereinafter described, for the purpose of protecting, the driving chains 7 from the burning fuel as well as providing an air draft by means hereinafter described, while each linl: plate 5 and6 is provided in its upper portion with a locking opening 25 into which an end ofthe bar 16; is adapted to fit and to be held ina fixed position. Each bar end cap 2e and 24?? comprises a body portion 26 from which extend downwardly on each side a lateral spacing, lug" or flange 27, between which at their base is an arched portion 28 adapted to surmount the flange of an end of the liar 16, the stem of which cooperates with the under side 25* and the flange coplates 5 and 6 in locking the bar 16 in a fixed position, whilethe flanges 27 are adapted to fit int-o corresponding; grooves 29 in the link plates 5 and 6 located in arms extending; above the grooves 25 thus being adapted to fasten the adjoining fuel plate 1;) and consequently the entire "row of cooperating fuel plates 15 on thebar 16, and the bar end cap 24 or 2 1?, as the case may be, in fixed position in the paired link plates or 6, so as to form a substantially rigid. and continuous fuel supporting si'ir'face clear across the bar 16. Above the body portion 26 of each bar end cap 2 and 24? are tapered tin-like members or segments'idO and 30" respectively, each having an upper fuel supporting surface 31, which is provided with a 101i 'tudinal center ridge 3. 5 and a beveled portion 31* on each sidefthereof, the center ridge 31 being arched or curved downwardly toward each end in the same manner as the center ridge 18 of the finllIS members 17 of the fuel plates 15, in order to keep theedges and the points, of the fin-like members 3O 3O out of the fire and thereby prevent their fusing.

In order to permit the bar end caps 2 and 248 to interfit and co-operate with each other in their travelthrough the furnace 2 and over the sprockets 12 and 13 some of. the bar end caps constitutingfll" are double, provided with two fin lilge neinbers or segments 30 while the 0th s constituting 2 are single, provided with one {in-like niei'nher or segment 30, the bar endcap's 2. and 24: being arranged in the chain? in alternation, successively one bar end'cap 2%" and then one. bar end cap 24', as shown' 1n Figs. 3, 4; and fi, so thatthe single fin-like member 30 of each bar end cap 24 wilhex tend into a draft space 32 between the double fin-like members 30" of each alignedbar'end cap 2 thereby leaving an air space between and entirely around the fin-like men' bers 30- and 36 clear to the fire level. i

In like manner the fuel plate 15 are arranged on the bar 16 and spaced apart by the spacing lugs 21, so that each of the fin-like members 17 eXtencs into a draft space 33between tin-like members 17 of adj oining fuel plates aligned therewith, thereby leaving an air space between and entirely around the in-like members 17 clear to the fire level,

as shown in Fig. 3, while in conjunction with the air space 32 surrounding the: finlike members 30 and 30 of'the bar end caps 2 and 241" on each end of the bar 16; the

fuelxplates 15. and bar end caps 245 and 24-" ll t bars t and bar end caps 24c and 24 are in consequence automatically cleared of any ashes forming a crust or clinkers, which are thereby removedfrom the draft spaces 32 and 33 of the bar end caps 24? and 2 11 and fuel plates 15 respectively.

The bar 16 is provided adjacent to veach end'with an opening 34:, extending through the flange of the bar 16, adapted to hold an inner cotter pin 35, between which cotter pins 35 inserted near each end of the bar 16 the fuel plates 15 are mounted in a row on the bar 16 and by which cotter pins 35 the fuel plates 15 are held in a fixed position on the bar 16.

Near the extremity of each end of the bar 16 in its flange is another opening" 36 adapted to hold an outer cotter pin 37, between which and the inner cotter pin 35 a bar end cap 24; or 24- is held in position on the bar 16, while the stem of the T-bar-16 is provided at each end with a notch 38 adapted to co-operate with the sides of the link plates 5 or 6, in which the ends of the bar 16 areinserted as previously described,

in holding the driving chains 7 in'spaced relation to each other and at a uniform distance apart.

lVhen itis necessary to employ one or more additional driving chains 7 across the grate bars 4, as shown in Fig. 2, Whiehfis generally the case, center bar caps 39 and 39? are used to hold the inner ends of each adjoining series of assembling bars 16, as shown in Fig. 2, being the same as the bar end caps 24 and 24" respectively, except that each center bar cap 39 and 39 is provided with a recess 10 in the arched portion 28 under the body portion 26, which recess 10 is adapted to receive a projection or stud 4:1 in the flange of each bar 16 near its inner end, the stud 41 by engaging one of the end walls 42 of the recess 10 being adapted to hold each bar 16 and its cc-operating center bar cap 39 or 39 in a fixed position in the grate 1. In assembling the center bar caps 39 and 39' with the grate bars 4; and chain link plates 5 and 6 given center bar cap is first placed in position in a given pair of spaced link plates, after which the outer end of a grate bar is tilted upwardly so as to follow the notched inner end of the grate bar 4% with the stud 41, which is short, to pass under the arched portion 28 of the center bar cap 39 or 39 and through the opening 25 of the 11111; plates, then the outer end of the grate bar 1 is lowered, the stud 11 coming into operative position and engaging the end wall 12 of the recess 40 of the center bar cap when the grate bar a has reached a horizontal position, then the co-operating center bar cap and grate bar 4 will be held together securely in the chain 7 operating in the center of the grate 1. The center bar caps and link plates are so made that the center bar caps fit loosely in the link plates thereby providing ample play to allow the grate bars and center bar caps to be readily assembled as described above.

The center bar caps 39' and 39" are provided with fin-like members or segments 39 and 39 respectively, ofthe same form and size as those of the bar end caps 24 and 2%, some of them 39 having two fin-like memhere or segments 39 and the others 39 c0- operating therewith having one fin-like member or segment 39, and they'are accordingly arranged in the chain link plates 5 and 6 of the center chain 7 in the same manner as the bar end caps 24 and 24 in the link plates of the outer chains 7, as shown in Fig. 2. The fin-like members 39 and 39 are each provided with an upper fuel supporting surface 39 divided longitudinally by an arched ridge 39 and having a beveled portion 39 on each side ot the ridge 39, being of the same form and size as similar parts of the bar end caps 24 and 24c", and the fuel plates 15, as shown in Fig. 3.

In order to maintain the series of fuel plates 15 on the assembling bar 16 in alignment so that the grate bar 4% will be substantially a solid bar, a lateral ear 13 is provided, extending from one of the two spacing lugs 21 on each side of a given fuel plate 15 and engaging a groove 4&4; in the cooperating spacing lug 21 of an adjoining fuel plate 15, thereby securing the entire series of fuel plates 15 on each assembling bar 16 in a rigid position.

In forming the driving chains 7 of successive pairs of spaced link plates 5 and 6, the inner link plates 5 are mounted on the pins 23 with the roller spacers 22 mounted between them and the outer link plates 6, which overlap the inner link plates 5. Each end of the pins 23 is provided with a hearing stud adapted to pass through. a circular opening 436 near each end of the paired and spaced inner link plates 5 and to turn freely therein, while an extended portion 17, provided with opposed flat surfaces 48, leading from each of the pins 23 extends through an opening 50 near each end of the co-operating paired and spaced outer link plates 6, the Hat surfaces 48 being adapted to engage similar fiat opposed sides 1-9 of the opening 50, while each pin extended, portion 47 is riveted on the end, thereby holding the outer link plates 6 in a fixed position as the chain 7 passes along and permitting the inner link plates 5 to turn on the bearing studs 4-5 and conse quently allowing the chain 7 to bend as the chain passes over the sprockets 12 and 13. Thus as the chain 7 travels along over the rollers 8, the upper portion of the chain being loose, the chain 7 drops between the rollers 8 and consequently an undulating movement is imparted to the chain 7, thereby causing the points or ends of the finlike members 30 30", 39, 39 and 17 of the bar end caps 24c and 2t the center bar caps 39 and 39 and the fuel plates 15 respectively, to rise and fall, which movement automatically cracks up the fuel bed, thereby permitting the air to pass freely through the fuel bed, and also constantly clears the draft spaces 32 and 33 of ashes, while as the grate bars 4: pass over the idler sprocket 13 the ends of each i'nterfitting row of fin-like members 17, 30 30 39 and 39 draw apart, thereby breaking up or shearing all clinkers or slag that has become attached to any of the fin-like members or any part of the grate.

The upper portion of the chain 7 travels on the rollers 8, which are mounted on the paired and spaced bearer bars 9 attached to cross bars or I-bars 51, while the lower portion of the chain 7 passes over rollers 52. Each bearer bar 9 has bearing lugs 53, which are located at certainintervalsthereon and opposite each other on the spaced bearer bars 9, while each bearing lug 53 is provided with a bearing chamber 5 1 substantially rectangular in shape and adapted to hold the spindle 55 of roller 8, as shown in Fig. 17, which spindle 55 turns freely in the opposed bearing chambers 54, each of which is provided with a clearance opening 56 in its end-Wall. Thus by employing the rectangular bearing chamber 54: with ample space therein surrounding the spindle 55, in conjunction with'the clearance opening 56, any ashes or clinkers entering each bearing chamber 54: are automatically removed through the clearance opening 56 and thereby the clogging of the bearing chamber 54 and consequent stopping of the rollers 8 are prevented.

All the parts of the grate bars a may be readily detached for repair or renewal, since when it is desired to remove a grate bar 4- or a bar end cap 24 or 24 the driving chains '7 are moved until the grate bar at and the bar end caps 24 and 24; are on the turn over either transversely aligned series of sprockets 12 or 13 operating the chains 7 in a given grate 1, when after the outer cotter pins 37 have been removed the bar end caps 24; and 24 may be readily detached and the grate bar l removed and a new one inserted, if desired, or after one of the inner cotter pins 35 has been removed the fuel plates 15 may be readily detached and replaced by new ones when necessary, thereby affording ready means for the removal and replacement of parts.

In operation the traveling grate l with the burning fuel thereon travels at the proper rate of speed through the furnace 2, the fuel plates 15 and bar end caps 24 and 24*, as

Well as the center bar caps 89 and 39 being held in a fixed position on the bar 16 with respect to the driving chains 7, the fin-like members 17, 30 30 39 and 39 of the fuel plates 15, bar end caps 24; and 24*, and center bar caps 39* and 39 respectively having an undulating movement as they move along, as previously described, and presenting a substantially solid upper fuel supporting surface and holding the burning fuel at an even thickness as it passes along, while the draft spaces 32 and 33 entirely surrounding the fin-like members 30, 30 39, 39 and 17 respectively, provide a substantially continuous air space at the fire level clear across and the entire length of the grate 1, thereby permitting a sufiicient volume of air to be evenly distributed throughout the entire fuel bed so as to pro duce a free combustion of the fuel throughout the fuel bed. By this arrangement of draft spaces the fuel plates 15, bar end caps 24? and 24: and center bar caps 89 and 39 are also adapted to be readily cleared of crusts and clinkers, as previously described, while they are moreover, constantly cooled by a draft of air and thereby prevented from fusing or burning.

I claim 1. In a traveling grate, a series of transversely aligned assembling bars, means for providing a sectional fuel bed comprising a series of fuel plates rhomboidal shaped in plan, motmted on each assembling bar and having their ends adapted to overlap to substantially the center of each adjoining as sembling bar and aligned end to end in rows.

2. In a traveling grate, a series of transversely aligned assembling bars, means for providing a sectional fuel bed comprising a series of fuel plates rho-mboidal shaped in plan, spaced apart and interfitting with each other and mounted on each assembling bar, the ends of the said fuel plates being adapted to overlap to substantially the center of each adjoining assembling bar, aligned end to end in rows and having a space between the ends of the said aligned fuel plates.

3. In a traveling grate, means for providing a sectional fuel bed comprising a series of fuel plates rhomboidal shaped in plan interfitting with each other and having draft spaces intervening between and entirely surrounding them clear to the fire level.

l. In a traveling grate, means for providing a sectional fuel bed comprising a series of fuel plates having their sides in plan tapered from the center toward each end and their upper edges co-extensive with the upper edges of the adjoining sides of col-operating fuel plates with which they interfit, and means for preventing the said fuel plates from buckling under the influence of heat comprising spacer lugs the base of the said fuel plates adapted to co-o-perate with the spacer lugs of adjoining fuel plates in holding the fuel plates out of contact wit-h each other, and providing draft spaces clear to the fire level.

5. In a traveling grate, a series of interfitting fuel plates, assembling bars for the said fuel plates, each fuel plate being provided with lateral spacing lugs below the fire level and at each side of the base of the said fuel plate, the said spacing lugs being llll) adapted to co-operate with the spacing lugs I of adjoining fuel plates in holding the cooperating fuel plates apart and in spaced relation to each other clear to the fire level, and a lateral ear extending from one of the said spacing lugs on each side of the said fuel plate and engaging a groove in the cooperating spacing lug of the adjoining fuel plate, the said ears and grooves being adapted to co-operate in holding the entire series of fuel plates in alignment on an assembling bar.

6. In a traveling grate, a series of detachable fuel plates, each fuel plate having an upper fuel supporting surface divided longitudinally by a ridge. with a beveled portion on each side thereof and in plan tapered from the center toward each end, the edges of the said fuel supporting surface being co-eXtensive. with the similar adjoining edges of co-operating fuel plates, assembling bars for the said fuel plates,

and bar end caps adapted to cover the ends of the said assembling bars, the said bar end caps being provided with segments, each segment having an upper fuel supporting surface divided longitudinally by a ridge with a beveled portion on each side thereof and in plan tapered from the center toward each end, the edges of the said upper fuel supporting surface being co-extensive with the similarly shaped edges of the upper fuel supporting surfaces of co-operating fuel plates and bar end caps.

7. In a traveling grate, assembling bars longitudinally aligned end to end across the grate, a series of fuel plates mounted on the said assembling bars, bar end caps for the outer ends of the said assembling bars, a stud on the inner end of each of the said assembling bars, and a center bar cap for the inner ends of adjoining longitudinally aligned assembling bars provided with a recess in the under side of the body portion adapted to receive the said stud-on the inner end of each of the said longitudinally aligned assembling bars.

8. In a traveling grate, a series of transversely aligned assembling bars, a series of fuel plates rhomboidal shaped in plan mounted on each assemblin bar, each fuel plate having an upper fuel supporting surface divided longitudinally by an arched ridge and having a beveled portion on each side thereof, and bar end caps adapted to cover the ends of the said assembling bars andprovided with fuel plate segments having upper fuel supporting surfaces, each fuel supporting surface being divided longitudinally by an arched ridge and having a beveled portion on each side thereof, the said bar end caps co-operating with the similarly shaped fuel plates and bar end caps adjacent thereto.

9. In a traveling grate, a series of fuel plates rhomboidal shaped in plan, each fuel plate having an upper fuel supporting surface divided longitudinally by an arched ridge and having a beveled portion on each side thereof, the said fuel plates being spaced apart and adapted thereby to form a continuous air space entirely around the fuel plates at the surface of the grate as well as clear across and the entire length of the grate, the said beveled portions having their lower edges CO-BXlJBIlSlVG with the similar lower edges of the beveled portions of adjoining fuel plates.

10. In a traveling grate, a series of trans versely aligned assembling bars, a series of fuel plates mounted on each assembling bar, bar end caps covering the ends the said assembling bar provided with downwardly extending, lateral flanges, driving chainsformed of a series of link plates, paired and spaced apart, each of the said link plates being provided with an upwardly eXtending arm on each side thereof and having therebetween an opening adapted to hold an end of the said assembling bar as well a groove in each of the said arms above the said opening, the flange and web of the said assembling bar fitting into the said opening and the said lateral flanges of the bar end cap into the said grooves, and cotter pins inserted in each end of each assembling bar on both sides of each bar end cap, thereby holding the said assembling bar and bar end cap securely in a stationary position in the said link plates and consequently the entire series of fuel plates on. the said assembling bar.

' 11. In a traveling grate, a series of grate bars, driving chains adapted to operate the said travelling grate, chain rollers under the upper portion of the said driving chains, each roller being provided-witha spindle, and bearer bars having bearing lugs forthe said chain rollers, each of which is provided with a substantially rectangular chamber adapted to hold the roller spindle and having a free clearance opening in its end wall, whereby the bearing chamber may be automatically cleared of any ashes or clinkers entering therein.

In testimony whereof I have afliXed my signature, in the presence of two witnesses.

FRANK B. FORREST.

Witnesses ED\VARD B. NoYns, FRANKLIN S. Fnisnnn. 

